CVE-2026-63802 (GCVE-0-2026-63802)

Vulnerability from cvelistv5 – Published: 2026-07-19 12:02 – Updated: 2026-08-05 12:35
VLAI
Title
blk-cgroup: fix UAF in __blkcg_rstat_flush()
Summary
In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: fix UAF in __blkcg_rstat_flush() When multiple blkgs in the same blkcg are released concurrently, a use-after-free can occur. The race happens when one blkg's __blkcg_rstat_flush() removes another blkg's iostat entries via llist_del_all(). The second blkg sees an empty list and proceeds to free itself while the first is still iterating over its entries. Move the flush from __blkg_release() (RCU callback) to blkg_release() (before call_rcu). This ensures the RCU grace period waits for any concurrent flush's rcu_read_lock() section to complete before freeing.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 20cb1c2fb7568a6054c55defe044311397e01ddb , < 96e545410c4f74c89d496c1d5d9ef8d08f14368b (git)
Affected: 20cb1c2fb7568a6054c55defe044311397e01ddb , < bbebd9425cad3573d1527441753899b926525a0f (git)
Affected: 20cb1c2fb7568a6054c55defe044311397e01ddb , < 5e5b7f2ef854936e95dceb6a2fdfefcb7152d2c6 (git)
Affected: 20cb1c2fb7568a6054c55defe044311397e01ddb , < afebe44facc48a61761e885bbb7f0380d4a603ec (git)
Affected: 20cb1c2fb7568a6054c55defe044311397e01ddb , < 0ab5ee5a1badb58cbb2242617cb01a4972b1f2a2 (git)
Affected: 0f6090d90f627d8c58f939067d6c6821ce1b3c68 (git)
Affected: 6.3.9 , < 6.4 (semver)
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Linux Linux Affected: 6.4
Unaffected: 0 , < 6.4 (semver)
Unaffected: 6.6.144 , ≤ 6.6.* (semver)
Unaffected: 6.12.95 , ≤ 6.12.* (semver)
Unaffected: 6.18.38 , ≤ 6.18.* (semver)
Unaffected: 7.1.3 , ≤ 7.1.* (semver)
Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix)
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      "status": "interim",
      "title": "SUSE CVE CVE-2026-63802",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-63802.json",
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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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